Boot and Shoe Machinery

BOOT AND SHOE MACHINERY. During the last 3o years shoemaking has undergone a complete change, due to the marked progress of mechanical equipment. Keen competition and close co-operation between Britain and America have greatly stim ulated development, which to-day must closely follow the dictates of fashion as well as produce bulk with certain and absolute uniformity.

The complex characteristics of shoemaking, the different types of footwear, alternative methods of making, and innumerable completely distinct operations resulting from great subdivision of labour, have made necessary a range of machines differing funda mentally in design and performance and varying greatly in type to an extent equalled in no other industry; very many different machines are used in the making of a single welted shoe; other types of footwear need equally distinctive machines. Machines are grouped into separate departments for distinctive work. Those which deal with the cutting, preparing and assembling of the upper are the clicking and closing departments. The bottom stock de partment cuts and prepares soles, insoles, etc., and includes the making of heels, stiffeners and welts. The section where the uppers and bottoms are assembled on the last and permanently joined is the making room, and the finishing department produces results that are not only attractive but necessary.

Upper Machinery.

While the greater proportion of upper components is cut by hand in Britain, many standard shapes and a greater number of fittings, i.e., tongue, backstraps, etc., are cut on a clicking press, a machine of the single revolution type, which presses a shallow knife through the leather on to a fibre or wood block. Machines for producing decorative features are nu merous. Perforating is done on a machine which makes a distinc tive design at one blow, or, alternately, on a machine with one punch holder, for giving a running design as the work is fed through. Involving these same general principles, folding machines are used for turning in and folding back the edges of vamps, caps, etc., after these have received a preliminary skiving and cementing. This produces a very attractively finished edge. Closing machines for sewing the upper components together attain speeds up to 4,0oo revolutions per minute and vary in type. There are "flat," "cylinder" and "post" machines, indicating the style of table over which the work is fed. There are chain-stitch and lock-stitch ma chines to sew one, two or four rows, with adjustments to vary the length of stitch, and some are fitted with under-trimming mechanism, so that the margin from edge to stitching is main tained uniform throughout.

Button-holing is done on a machine capable of cutting and working 22 holes per minute, and a button sewing machine will automatically feed and attach with 16 stitches to each, approxi mately 6o buttons per minute. Eyeletting and hoolcing machines are similar in operation. Eyelets, fed from a rotating hopper, gravitate along a chute into holes punched and spaced auto matically, and are then clinched. To hold eyeletted uppers in posi tion for lasting, these are temporarily laced by a machine which will tie over from one to four pairs of holes, and at the same time securely knot the thread.

Bottom Stock.

Soles, middlesoles and insoles are pressed out. A most widely used machine is the revolution press, a quick ac tion machine with a heavy beam. The cutting block is of wood or compressed fibre, and shaped knives 4 in. deep are used. The beam descends on to a 4 in. deep knife upon the operator tripping the machine, the knife being moved along after each cut. Soles, etc., are frequently cut to a standard pattern and later trimmed to a particular shape on the rounding machine. A clamp holds sole and wood pattern in position while a knife, with its cutting edge level with the sole, and held to the former by a spring, traverses the complete periphery, giving the desired shape and a square edge. A stamping machine used for recording size, fitting shape, tannage and other information will give io,000 different markings and maintain a uniform depth of impression irrespective of sub stance. Channelling machines play an important part in the prep aration of soles and also welted insoles. Outsoles are prepared by having an oblique incision or a groove cut parallel to the edge of the sole in which the stitches are buried when the sole is attached, a channelling knife being used to suit the type of seam to be made. In preparing the welt insole an entirely different machine of more intricate design is needed to cut an inside channel and an outside lip at the same time, and with such accuracy that the substance between these two channels is maintained uniform. Subsidiary machines open these channels and perform other minor operations. Sole and insole moulding machines are commonly used with various types of shoes, and particularly women's, where more ex treme shapes are met. A preliminary shape is given by this ma chine, which, using vertical pressure, actuated by toggle motion, moulds the sole to the shape of the last between upper and lower moulds. The machine is alternating, one mould being fed while the other is under pressure.

Heel Building Machines.—Heel lifts and top pieces are gen erally blanked out on a small press similar to the clicking press. A rand, or bevelled strip of leather, is sometimes attached to the seat lift by a tacicing machine, which also employs a slashing knife to facilitate the conformation of the flat strip to the curved out line of the heel. The heel building machine itself carries a mould into which the lifts are fed and held in position while nails are driven at one blow. Heels are compressed on a powerful machine, and acting automatically, as one heel is fed the previous one is ejected. The top piece is generally attached with a slugging machine, which takes its name from the kind of nail used. This is a length of wire cut from a coil and with no head or point. The "breasting" of the front of the heel is done with a gouge of the required curve fixed to a machine with an adjustable table which enables the correct angle of cut to be obtained.

Assembling and Making operation of pulling over is performed on a machine of ingenious design and great precision. It is to this machine that the insoles and uppers are brought, assembled on the last, with stiffener and toe puff in position. The upper is gripped by three or five pincers, one or two on each side of forepart and one in centre at toe, and tension is applied to draw it tightly over the last after it has been straight ened to the satisfaction of the operator by the manipulation of various convenient adjustments. The pull on the pincers is ad justable to suit the lightest fabric or toughest leather, is applied steadily, and is sensitively controlled by an oil buffer. In the second cycle five or seven tacks are driven through upper and in sole, retaining the whole in position. The tacks are delivered to the required position by an air blast, which blows them point f ore most through conducting tubes, the timing being in perfect unison with the whole sequence of movements. The machine is wonder fully adaptable, admitting all sizes from children's to men's. The lasting machine used in conjunction with the above completes the work as it was formerly performed by hand. The machine uses a single twisting pincer which pleats the surplus upper drawn over the last, and drives tacks delivered from a rotating tack pot. The pounding up machine hammers the tacks home and grinds to a level the bunched upper at the toe. Operations now vary according to the type of shoes and consequently the machines also. Impor tant methods of making shoes include welt, machine sewn, turn shoe, veldt, littleway, etc. Dealing with the two first mentioned, the foregoing operations are all performed mechanically, but only the chief machines are described. Af ter lasting, the surplus upper is removed, staples of fine wire substituted for the lasting tacks, which are withdrawn in order to offer no impediment to the needle of the welt sewing machine. This machine makes .a . horizontal seam, in which respect it imitates the work of the hand welt sewer. Making a chain stitch of three or four to the inch it uses a curved needle and produces a tight horizontal seam, through welt, upper and the insole lip. A channel guide indicates the point where the needle will pierce through, and helps to steady the work. A hot waxed thread is used and the machine is heated by steam or elec tricity. Each stitch is pulled tight, regardless of the substance of the material or variation in speed of machine. Surplus material is closely trimmed on a machine specially designed to obviate dam age to the seam. The welt is beaten out flat. The machine used for this purpose carries a reciprocating hammer and incorporates a. slashing knife for assisting round the toe. The ends of the welt are both skived off simultaneously to any desired angle, and two tacks driven to hold permanently in position on a welt butting and tacking machine. The bottom is filled, shank inserted and sole attached. The shoe, with the last in, is placed under pressure in the sole-laying machine to cause the sole to follow closely the con tour of the last. The rounding and channelling machine performs an important work. It roughly trims the edge of the sole, and at the same time cuts a channel parallel to the edge to receive the stitches. An arrangement of adjustable guides mechanically de termine the finished shape or contour, which is cut by a chisel shaped knife. A high speed lockstitch sewing machine, with to tally-enclosed mechanism and a needle automatically lubricated, is generally used for fastening the sole to the welt, in which uni formity and tightness of stitches is of paramount importance. The needle and shuttle threads are gummed or waxed and the machine is heated by steam or electricity. After lasting and pounding up as previously mentioned the shank is inserted, and the sole tem porarily attached by a wire grip tacking machine, which cuts, points, and drives any desired length of headless tack from a coil of wire. The permanent attachment in this type of shoe is then made direct through sole and insole, taking in the lasted upper at the same time. The shoe with last removed is placed on the horn of the improved Blake sewing machine, and the needle or hook which combines the duties of awl and needle, pierces the sole so that the barb of the hook projects through the insole, where it takes up the thread passed through the horn. A waxed or gummed thread is used and the machine is generally heated by gas. A chain or crochet stitch is made, each tightened by its successor, the length being variable from three to seven to the inch. Metallic fastenings of various kinds are used for permanent attachment on some classes of shoes. One of these is made by the rapid screwing machine, which, using a coil of steel or brass wire, threaded with a regular pitch, automatically cuts off and clinches at the correct length the screws with which it secures at the rate of 25o per minute at a regular and adjustable spacing. Levelling the bottom is an operation common to most types of footwear. Two distinct types of machines are employed. The roller type uses a rapidly vibrating roller which sleeks the bottom of the shoe while on the last, pressure being applied successively over the whole surface. The direct pressure type operates with a crank motion, an iron foot on which the shoe is placed swinging under a mould of par ticular shape. Later developments of this pattern have produced a machine equally effective with work on or off the last which, by a peculiar rocking motion, embodies the advantages of both types. In each case the alternating design admits of one shoe being under pressure while the other is removed and replaced. Machines for attaching heels are stoutly built to withstand the great pressure that is necessary to drive up to 16 nails either from inside or out side the shoe. Automatic nail loaders are attached which replace the required number of nails into the attaching stand ready for the next heel. Any desired pressure can be uniformly applied, the nails being driven by two distinct blows which eliminate the possi bility of springing back. Machines have been specially designed for the fitting of Louis and other wood heels. One automatically gauges shoes for correct position from the actual heel.

Finishing Machinery.—High speed ball bearing machines for trimming, scouring and polishing, constitute the major group for this section. When necessary they are provided with means for exhausting dust. The rough heel is trimmed to shape on the heel trimming machine which carries two cutters, moulded to the re verse shape of the heel, in the rotating head, which automatically adjusts itself to variations in height of heel. Edge trimming ma chines produce the shape of the finished edge of foreparts and waists with specially formed cutters which are readily interchange able. The latest machines include reciprocating planing knives which blend the juncture of the heel and waist trimming. Marked features of these trimming machines are their solidarity, eliminat ing vibration, and their convenience of operation. Scouring and buffing machines for smoothing the surface of heels and bottoms are similar in general principles, differently shaped rolls of various types, covered with sandpaper, or other abrasive material that can be quickly replaced, being mounted on shafts speeded to give a uniform velocity. Edge setting is a process that requires pressure and friction, and the automatic edge setting machine has been designed to perform this heavy duty entirely mechanically. The shoe is clamped in a travelling jack, the movement of which is controlled through hydraulic action, while a rapidly vibrating heated tool is forced against the edge with uniform pressure which can be varied to suit the lightest or heaviest work. The machine adapts itself to all sizes and represents the furthest step yet made toward automatic shoemaking machinery. Heated machines em ploying metal or other rolls, burnish heels and bottoms, distribut ing a film of wax over the surface, and others emboss the sole with trade mark or price, scour and repair the surface of patent leather, and withdraw the last.

With the more universal employment of electric power, many machines have been designed to embody their own individual mo tors, and this policy is being continued, so that the arrangement of a complete plant may shortly be unaffected by limitations prev alent to-day because of the restricted means for driving. Machines which require heat are also being adapted to the use of electricity, and the extensive use of ball bearings is making a marked reduc tion in running costs. Close attention is being paid to the incor poration of safety devices and progress will probably lean toward the introduction of more completely automatic machinery.

Machinery in the United States.—In the making of some types of shoes there are required as many as 210 handlings after the order is received in the factory, embracing as many as machine operations, 154 of which are performed on different machines, there being a duplication in only 20 instances. There are, in America, six manufacturing methods, standard screw, McKay sewed, Goodyear welt, Goodyear turned, littleway and stitchdown, utilizing various types of machines. The standard screw method is used almost entirely for reinforcing certain por tions in the heavier and more rugged types of soled shoes. The McKay sewed shoe method was still in wide use in 1928 having an extended field through the advent of the types of close edged soles in imitation of the appearance of the turned shoes. The turned shoe is made as its name implies, wrong side out, and as it has no insole, it is very flexible. It is a type which was very popular in the light-soled dainty slippers of the period beginning back at least in the 14th century and which has continued up through 1928. The most distinctive American methods are the stitchdown and the Goodyear welt. The stitchdown differs in principle from others in using an insole tacked to the bottom of the last, the shoe upper being drawn over it. The lining is cemented to the surface of the insole. A second middle sole is laid, larger in size and cemented to the insole. The outsole is cemented to this middle sole and the stitching machine unites out sole, middle sole, shoe upper and a small welt is fed through the machine to make a complete union of these different members, the welt being used to give greater security to the stitch and also to bring the thickness of the sole up to the level of the surface of the insole. The Goodyear welt shoe is probably more widely worn than any other, it being adapted to the greatest range of uses. Most men's shoes at the present time, in America particu larly, are made by this process and up to 1928 it was still very widely used in producing women's shoes, as well as those even for children and infants. When an order is received at a factory using the Goodyear welt method, the details regarding all of the material are carefully written out on tags, one of which usually goes to the division of the factory known as the cutting room and contains those details regarding the kind of leather, colour, the design to be employed, the number and sizes to be made. After the parts have been cut out by means of thin steel dies they are then sent to the stitching room and are there fashioned into the complete shoe upper with all of the various linings, stays, buttons, facings, eyelets and other parts which are required. On the com pletion of this work the shoe uppers are sent to the bottoming mom and soled. The insole is first channeled by a machine which cuts a little slit along the edge and on the one which extends toward it. These lips are afterwards turned up so that they stand out at a right angle to the surface of the insole in order that the greatest strength and flexibility may be achieved.

Fabrication.

The insoles which are then the exact size and shape of the bottom of the last are tacked in place. The shoe upper is assembled, the operator in this case placing the counter in its proper position between the lining and the foxing in the heel portion of the shoe, as well as the toe box which gives per manent form to the toe of the shoe, putting the back seam of the shoe upper in correct position on the heel of the last. In the stitching room the shoe uppers are laced in order that they may be held in proper position on the last. A machine laces them and automatically ties a bow knot. The assembled shoe is then presented to an assembling machine and two tacks are driven, one just beside the back seam and one just over the edge of the insole at the heel, holding the shoe upper securely in place at these points. The shoe is then pulled over by a machine which permits the operator to adjust quickly the position of the shoe upper on the last so that the shoes have toe caps which are square across and of the proper length in each instance. Prior to the use of this machine this was one of the most difficult operations in shoe production. The operator corrects the position of the shoe upper and the sides of the shoe are then lasted. The toe and heel are next lasted, tacks being driven at the heel and toe, held in place temporarily by wire which lies in the crimp of the leather. There then follows another stapling machine which staples the toe portion to the lip of the insole so that the wire may be re moved. These staples have made negligible the large loss which formerly accrued through the breaking of needles and cutting of thread. The surplus portion of the shoe upper and lining are now trimmed away and the welt is sewn. It is a narrow strip of leather sewn from a point beginning at the breast of the heel on one side to a like position on the opposite side of the shoe, going around the forepart. The curved needle in the machine enters the welt and then pierces the shoe upper, the lining and the lip with its canvas reinforcement on the surface of the insole. It does not go inside the shoe. There is then spread over the surface of the insole a material generally made of ground cork and rubber cement to make up the difference in height occasioned by the addition of the welt. This serves as a cushion under the foot and with it there is generally placed the shank piece which is intended to give permanent form to the shank of the shoe. Tacks are withdrawn at this time from the forepart of the shoe, and the surface of the welt and the filling are given a coat of rubber cement and the heavier insole which is cut to the required shape is also coated with rubber cement. The sole is laid or pressed into place in proper position by a machine which has one shoe under pressure while the other is being prepared. The shoe is then rounded, the edges being cut to the required shape and the shoe is given its style. The shape of the sole and its relation to the lasted shoe is of great importance. Incidental to this operation the machine cuts a little channel in the edge of the sole which is afterwards turned back by a machine in order that there may be a clear path for the needle of the stitching machine which unites the outsole to the welt. The thread used is very strong and is coated with hot wax, beng maintained in that condition until it is actually set in the leather. The channel is coated with rubber cement and a machine rubs the lip down smoothly to conceal the stitches. The shoe is then levelled by rolls under heavy pressure, rolling out any unevenness which may be in the forepart of the shoe. The heel portion of the outsole is then nailed in place, the nails going through the outsole and clenched against the steel heel piece on the last. Many have rubber top lifts attached to them. The nails in most men's shoes with leather heels are all driven at one time and are clenched against the steel bottom of the last. The rough lifts of the heel are then trimmed to the required shape by means of the rapidly revolving knives of a trimming machine and the breast of the heel is cut to the required shape by a downward thrust of a knife, the movement of which is very accurately gauged. By various scouring operations the breast of the heel is brought to a smooth surface. Then follows a machine which blacks the heel, followed by another machine which coats the surface with hot wax and burnishes it to a lasting finish. The forepart of the shoe is also treated and trimmed very smoothly to the required bevel and shape by rapidly revolving knives on the trimming machine, two cutters being used, one for the fore part and one in the shank where the bevel is changed. These edges are also coated with wax and are burnished by means of hot irons electrically heated, vibrating very rapidly. The bottom of the shoe is then buffed, all the stains gathered in the manu facturing process being removed by rapidly revolving wheels covered with abrasive. The shank of the shoe receives special treatment on a machine on which there are two pads revolving as rapidly as 7,50o times per minute, cooled by a pressure of air from a pump which is a part of the machine. There follow a variety of waxings and finishing operations varying with the type of the shoe. The treeing machine is then employed for ironing out wrinkles and removing any stains on the shoe, and after a final brushing and careful inspection the shoes are ready for packing and shipment. (A. D. AN.)